Cisco1721 + 2 x Wic1-ADSL

[anka_ozcan]

Hi ,

I have Cisco 1721 router with two Wic1-ADSL cards, I wanna setup an internet connection over two ADSL lines. However, I want that router must automatically balance the total bandwidth, in other words router should balance all traffic on these two lines (load sharing/balancing) and also if a problem occur at one of this connections, router should automatically forward requests to 2.nd ADSL line (may be called redundancy or something like that). Please, I really need such a solution urgently, here is my current configuration (below), with this configuration only ATM1 is working. Thank for your helps.

-------------

!

hostname Anka1_1721

!

enable password ************

!

ip subnet-zero

ip name-server 212.156.4.4

ip name-server 212.156.4.1

!

interface ATM1

no ip address

no ip mroute-cache

no atm ilmi-keepalive

dsl operating-mode auto

no fair-queue

ip load-sharing per-packet

!

interface ATM1.1 point-to-point

pvc 8/35

pppoe-client dial-pool-number 1

!

!

interface ATM0

no ip address

no ip mroute-cache

no atm ilmi-keepalive

dsl operating-mode auto

no fair-queue

ip load-sharing per-packet

!

interface ATM0.1 point-to-point

pvc 8/35

pppoe-client dial-pool-number 2

!

!

interface FastEthernet0

description +++ LAN +++

ip address 10.0.0.130 255.255.255.0

ip nat inside

ip tcp adjust-mss 1452

speed 100

hold-queue 100 out

half-duplex

!

!

interface Dialer1

description +++ TTNet ADSL via ATM1 +++

ip address negotiated

ip mtu 1492

ip nat outside

encapsulation ppp

dialer pool 1

dialer-group 1

no cdp enable

ppp authentication pap callin

ppp pap sent-username ******* password *******

!

!

interface Dialer0

description +++ TTNet ADSL via ATM0 +++

ip address negotiated

ip mtu 1492

ip nat outside

encapsulation ppp

dialer pool 2

dialer-group 2

no cdp enable

ppp authentication pap callin

ppp pap sent-username ******@ttnet password ******

!

ip classless

ip route 0.0.0.0 0.0.0.0 Dialer1

ip route 0.0.0.0 0.0.0.0 Dialer0

ip route 10.0.0.0 255.255.255.0 FastEthernet0

!

ip http server

no ip http secure-server

!

ip nat inside source list 101 interface Dialer0 overload

ip nat inside source list 101 interface Dialer1 overload

ip nat inside source static 10.0.0.100 10.0.1.100

!

access-list 1 permit 10.0.0.0 0.0.0.255

access-list 101 permit ip 10.0.0.0 0.0.0.255 any

dialer-list 1 protocol ip permit

dialer-list 2 protocol ip permit

!

line vty 0 4

password *******

login

!

[tekha]

I take it you do get IP's on both ATM subinterfaces, is that right?

For equal, per-destination loadbalancing over both interfaces see this: http://forum.cisco.com/eforum/servlet/NetProf;jsessionid=xa8x8enn61.SJ1A?page=netprof&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40.1dd7430b/1#selected_message

For the "redundancy" see this: http://www.cisco.com/en/US/products/sw/iosswrel/ps5413/products_feature_guide09186a00801d862d.html#wp1066247

[anka_ozcan]

Hi, i tried to implement your advice to my configuration, unfortunately no connetion. In shortly I need load balancing on two ADSL lines, my ISP gives dynamic IP's for both lines. Last configuration is below, I am inexpreienced in routing, if you explaind in details i will be happy, Thank you.

!

hostname Anka1_1721

!

enable password *****

!

ip subnet-zero

ip name-server 212.156.4.4

ip name-server 212.156.4.1

!

interface ATM1

no ip address

no ip mroute-cache

no atm ilmi-keepalive

dsl operating-mode auto

no fair-queue

!

interface ATM1.1 point-to-point

pvc 8/35

pppoe-client dial-pool-number 1

!

!

interface ATM0

no ip address

no ip mroute-cache

no atm ilmi-keepalive

dsl operating-mode auto

no fair-queue

!

interface ATM0.1 point-to-point

pvc 8/35

pppoe-client dial-pool-number 2

!

!

interface FastEthernet0

description +++ LAN +++

ip address 10.0.0.130 255.255.255.0

ip nat inside

ip policy route-map pbr

ip tcp adjust-mss 1452

speed 100

half-duplex

!

!

interface Dialer1

description +++ TTNet ADSL via ATM1 +++

ip address negotiated

ip mtu 1492

ip nat outside

encapsulation ppp

dialer pool 1

dialer-group 1

no cdp enable

ppp authentication pap callin

ppp pap sent-username ******@ttnet password ********

!

!

interface Dialer0

description +++ TTNet ADSL via ATM0 +++

ip address negotiated

ip mtu 1492

ip nat outside

encapsulation ppp

dialer pool 2

dialer-group 2

no cdp enable

ppp authentication pap callin

ppp pap sent-username ******@ttnet password ******

!

ip classless

ip route 0.0.0.0 0.0.0.0 Dialer1

ip route 0.0.0.0 0.0.0.0 Dialer0

ip route 10.0.0.0 255.255.255.0 FastEthernet0

!

ip http server

!

ip nat inside source route-map Dialer0 interface Dialer0 overload

ip nat inside source route-map Dialer1 interface Dialer1 overload

ip nat inside source static 10.0.0.100 10.0.1.100

!

access-list 97 permit 10.0.0.0 0.0.0.255

access-list 98 permit 10.0.0.0 0.0.0.255

dialer-list 1 protocol ip permit

dialer-list 2 protocol ip permit

!

route-map pbr permit 10

match ip address 97

match interface Dialer0

!

route-map pbr permit 20

match ip address 98

match interface Dialer1

!

line vty 0 4

password *************

login

!

[tekha]

OK, then no explanation, just configuration.

Start by doing a "sh ip int brie", do both ATM subinterfaces have an IP address?

Then write the following.

ip cef

no ip route 10.0.0.0 255.255.255.0 FastEthernet0

no route-map pbr

route-map Dialer0 permit 10

match ip address 97

match interface Dialer0

!

route-map Dialer1 permit 10

match ip address 98

match interface Dialer1

Now you should be able to see 2 default routes in the route-tabel, when doing a "sh ip route", is that correct?

If you do a check from http://www.google.com/search?hl=en&q=my+ip+address&btnG=Google+Search, clicking on the links, you should see that the different websites, states 2 different IP's, right?

[odemiguel]

Hi tekha,

I have a question about the configuration. When you configured the two route-map, you introduce the ip policy command on the ethernet interface, or on each dialer interface ??

Thanks

[justin.white]

Your configuration should already support equal cost load balancing, but you need to understand what it is you are asking. Your configuration has two, equal cost, static, default routes. These two routes should both appear in your routing table when you issue the "show ip route" command like so:

S* 0.0.0.0/0 [1/0] via Dialer0

S* 0.0.0.0/0 [1/0] via Dialer1

If that is the case (i.e. please check your routing table), then you need to decide which type of load balancing you want to use. Based on your posted configuration, the router is already configured for Per-Destination load balancing (meaning that each IP stream or flow will alternate between up to four routes in most cases). While this approach is fine for most environments, it will almost certainly leave an unequal distribution of bandwidth used between the available links.

Since you want to even distribute bandwidth, you need to use Per-Packet load balancing, which alternates between available routes on a per-packet basis, regardless of destination. While this approach will result in better distribution of bandwidth, it will also present problems with out-of-sequence packets and address translation. Since you are using NAT, I would recommend keeping your existing configuration (even with the lack of true sharing for bandwidth between the two links).

Here's the best references I could find to illustrate what I just stated:

http://www.cisco.com/warp/public/105/46.html (How does load balancing work?)

http://www.cisco.com/en/US/products/hw/modules/ps2033/prod_technical_reference09186a00800afeb7.html (Load balancing with CEF)

Hope this helps,

JW

--

Justin White, CCIE #14745, MCSE

whitej@gmx.net

[odemiguel]

I have this configuration:

interface FastEthernet0/0

ip address 10.10.1.1 255.255.0.0

no ip redirects

no ip proxy-arp

ip nat inside

ip tcp adjust-mss 1452

no ip mroute-cache

duplex auto

speed auto

!

interface FastEthernet0/1

ip address 192.168.1.10 255.255.255.0

shutdown

duplex auto

speed auto

!

interface ATM0/0/0

no ip address

no atm ilmi-keepalive

bundle-enable

dsl operating-mode auto

!

interface ATM0/0/0.1 point-to-point

pvc 8/32

pppoe-client dial-pool-number 1

!

!

interface ATM0/1/0

no ip address

no atm ilmi-keepalive

bundle-enable

dsl operating-mode auto

!

interface ATM0/1/0.1 point-to-point

pvc 8/32

pppoe-client dial-pool-number 2

!

!

interface Dialer1

mtu 1492

ip address negotiated

ip nat outside

encapsulation ppp

ip policy route-map adsl1

dialer pool 1

ppp authentication pap chap callin

ppp chap hostname xxxxxxxxxx

ppp chap password 7 00051715084B1B16

ppp pap sent-username xxxxxxxxxxxx

password 7 yyyyyyyyyyy

!

interface Dialer2

mtu 1492

ip address negotiated

ip nat outside

encapsulation ppp

ip policy route-map adsl2

dialer pool 2

ppp authentication pap chap callin

ppp chap hostname xxxxxxxxxxxxx

ppp chap password 7 yyyyyyyyyyy

ppp pap sent-username xxxxxxxxxx

password 7 yyyyyyyyy

!

ip classless

ip route 0.0.0.0 0.0.0.0 Dialer2

ip route 0.0.0.0 0.0.0.0 Dialer1

!

ip http server

ip http authentication local

ip http timeout-policy idle 600 life 86400 requests 10000

ip nat inside source route-map adsl1 interface Dialer1 overload

ip nat inside source route-map adsl2 interface Dialer2 overload

!

access-list 3 permit any

route-map adsl2 permit 10

match interface Dialer2

!

route-map adsl1 permit 10

match interface Dialer1

I would like to know if this configuration will permit lan connect to the internet through the two adsl.

I'm no sure about the nat and route-map configuration.

Please, help as much as you can.

Thanks in advance

[tekha]

Looks pretty allright to me.

The route-map/NAT configuration is to let the router

NAT all internal addresses to the address of the interface its traversing.

If you have enabled ip cef, your interfaces should be running ip load-sharing per-destination, which it should. If you haven't allready enabled CEF, then please do. (ip cef)

You don't need the "ip policy route-map" on the Dialer interfaces, so remove those.

Could you do a "sh ip cef internal" and "sh ip nat stat", and post the results here.

Yhat would give us a hint, to see if it's working or not.

[odemiguel]

Now, I don't have the two adsl lines to connect and make proves.

But I have this message doing "sh ip cef internal" and "show ip nat stat":

r1841_aud#show ip cef inter

IP CEF with switching (Table Version 6), flags=0x0

5 routes, 0 reresolve, 0 unresolved (0 old, 0 new), peak 0

5 leaves, 8 nodes, 9136 bytes, 13 inserts, 8 invalidations

1 load sharing elements, 376 bytes, 1 references

universal per-destination load sharing algorithm, id CB41AB75

3(1) CEF resets, 1 revisions of existing leaves

Resolution Timer: Exponential (currently 1s, peak 1s)

1 in-place/0 aborted modifications

refcounts: 2312 leaf, 2304 node

Table epoch: 0 (5 entries at this epoch)

0.0.0.0/0, version 4, epoch 0, attached, per-destination sharing

0 packets, 0 bytes

via Dialer2, 0 dependencies

traffic share 1

valid punt adjacency

via Dialer1, 0 dependencies

traffic share 1

valid punt adjacency

0 packets, 0 bytes switched through the prefix

tmstats: external 0 packets, 0 bytes

r1841_aud#show ip nat stat

Total active translations: 0 (0 static, 0 dynamic; 0 extended)

Outside interfaces:

Dialer1, Dialer2

Inside interfaces:

FastEthernet0/0

Hits: 0 Misses: 0

CEF Translated packets: 0, CEF Punted packets: 0

Expired translations: 0

Dynamic mappings:

-- Inside Source

[Id: 1] route-map adsl1 interface Dialer1 refcount 0

[Id: 2] route-map adsl2 interface Dialer2 refcount 0

Queued Packets: 0

I supose that you want to see this commands with the two lines connectec, but I can do this until next week.

Can you explain me why "ip policy route-map" command are not necessary on dialers interfaces?

Thank you very much.

[tekha]

We don't want to use the 2 route-maps for policy-routing, only for the NAT translation.

We will let CEF and load-sharing per-destination, figure out which interface to use.

And the NAT statements will then NAT the destination address, to whatever IP address the the packet is traversing.

From the output you can see that you have 2 default routes, one via Dialer1 and the other via Dialer2. And using Per-destination load-sharing.

0.0.0.0/0, version 4, epoch 0, attached, per-destination sharing

0 packets, 0 bytes

via Dialer2, 0 dependencies

traffic share 1

valid punt adjacency

via Dialer1, 0 dependencies

traffic share 1

valid punt adjacency

And these 2 statements in the "sh ip nat stat":

[Id: 1] route-map adsl1 interface Dialer1 refcount 0

[Id: 2] route-map adsl2 interface Dialer2 refcount 0

Means that your are natting on 2 different interfaces.

It looks like this would work.